1 /* -*- c -*- --------------------------------------------------------------- *
3 * linux/fs/autofs/waitq.c
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 * Copyright 2001-2006 Ian Kent <raven@themaw.net>
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
12 * ------------------------------------------------------------------------- */
14 #include <linux/slab.h>
15 #include <linux/time.h>
16 #include <linux/signal.h>
17 #include <linux/file.h>
20 /* We make this a static variable rather than a part of the superblock; it
21 is better if we don't reassign numbers easily even across filesystems */
22 static autofs_wqt_t autofs4_next_wait_queue
= 1;
24 /* These are the signals we allow interrupting a pending mount */
25 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
27 void autofs4_catatonic_mode(struct autofs_sb_info
*sbi
)
29 struct autofs_wait_queue
*wq
, *nwq
;
31 mutex_lock(&sbi
->wq_mutex
);
33 mutex_unlock(&sbi
->wq_mutex
);
37 DPRINTK("entering catatonic mode");
41 sbi
->queues
= NULL
; /* Erase all wait queues */
44 wq
->status
= -ENOENT
; /* Magic is gone - report failure */
50 wake_up_interruptible(&wq
->queue
);
53 fput(sbi
->pipe
); /* Close the pipe */
56 mutex_unlock(&sbi
->wq_mutex
);
59 static int autofs4_write(struct file
*file
, const void *addr
, int bytes
)
61 unsigned long sigpipe
, flags
;
63 const char *data
= (const char *)addr
;
66 /** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/
68 sigpipe
= sigismember(¤t
->pending
.signal
, SIGPIPE
);
70 /* Save pointer to user space and point back to kernel space */
75 (wr
= file
->f_op
->write(file
,data
,bytes
,&file
->f_pos
)) > 0) {
82 /* Keep the currently executing process from receiving a
83 SIGPIPE unless it was already supposed to get one */
84 if (wr
== -EPIPE
&& !sigpipe
) {
85 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
86 sigdelset(¤t
->pending
.signal
, SIGPIPE
);
88 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
94 static void autofs4_notify_daemon(struct autofs_sb_info
*sbi
,
95 struct autofs_wait_queue
*wq
,
99 struct autofs_packet_hdr hdr
;
100 union autofs_packet_union v4_pkt
;
101 union autofs_v5_packet_union v5_pkt
;
103 struct file
*pipe
= NULL
;
106 DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
107 wq
->wait_queue_token
, wq
->name
.len
, wq
->name
.name
, type
);
109 memset(&pkt
,0,sizeof pkt
); /* For security reasons */
111 pkt
.hdr
.proto_version
= sbi
->version
;
114 /* Kernel protocol v4 missing and expire packets */
115 case autofs_ptype_missing
:
117 struct autofs_packet_missing
*mp
= &pkt
.v4_pkt
.missing
;
121 mp
->wait_queue_token
= wq
->wait_queue_token
;
122 mp
->len
= wq
->name
.len
;
123 memcpy(mp
->name
, wq
->name
.name
, wq
->name
.len
);
124 mp
->name
[wq
->name
.len
] = '\0';
127 case autofs_ptype_expire_multi
:
129 struct autofs_packet_expire_multi
*ep
= &pkt
.v4_pkt
.expire_multi
;
133 ep
->wait_queue_token
= wq
->wait_queue_token
;
134 ep
->len
= wq
->name
.len
;
135 memcpy(ep
->name
, wq
->name
.name
, wq
->name
.len
);
136 ep
->name
[wq
->name
.len
] = '\0';
140 * Kernel protocol v5 packet for handling indirect and direct
141 * mount missing and expire requests
143 case autofs_ptype_missing_indirect
:
144 case autofs_ptype_expire_indirect
:
145 case autofs_ptype_missing_direct
:
146 case autofs_ptype_expire_direct
:
148 struct autofs_v5_packet
*packet
= &pkt
.v5_pkt
.v5_packet
;
150 pktsz
= sizeof(*packet
);
152 packet
->wait_queue_token
= wq
->wait_queue_token
;
153 packet
->len
= wq
->name
.len
;
154 memcpy(packet
->name
, wq
->name
.name
, wq
->name
.len
);
155 packet
->name
[wq
->name
.len
] = '\0';
156 packet
->dev
= wq
->dev
;
157 packet
->ino
= wq
->ino
;
158 packet
->uid
= wq
->uid
;
159 packet
->gid
= wq
->gid
;
160 packet
->pid
= wq
->pid
;
161 packet
->tgid
= wq
->tgid
;
165 printk("autofs4_notify_daemon: bad type %d!\n", type
);
169 /* Check if we have become catatonic */
170 mutex_lock(&sbi
->wq_mutex
);
171 if (!sbi
->catatonic
) {
175 mutex_unlock(&sbi
->wq_mutex
);
178 if (autofs4_write(pipe
, &pkt
, pktsz
))
179 autofs4_catatonic_mode(sbi
);
184 static int autofs4_getpath(struct autofs_sb_info
*sbi
,
185 struct dentry
*dentry
, char **name
)
187 struct dentry
*root
= sbi
->sb
->s_root
;
198 seq
= read_seqbegin(&rename_lock
);
200 spin_lock(&sbi
->fs_lock
);
201 for (tmp
= dentry
; tmp
!= root
; tmp
= tmp
->d_parent
)
202 len
+= tmp
->d_name
.len
+ 1;
204 if (!len
|| --len
> NAME_MAX
) {
205 spin_unlock(&sbi
->fs_lock
);
207 if (read_seqretry(&rename_lock
, seq
))
213 p
= buf
+ len
- dentry
->d_name
.len
;
214 strncpy(p
, dentry
->d_name
.name
, dentry
->d_name
.len
);
216 for (tmp
= dentry
->d_parent
; tmp
!= root
; tmp
= tmp
->d_parent
) {
218 p
-= tmp
->d_name
.len
;
219 strncpy(p
, tmp
->d_name
.name
, tmp
->d_name
.len
);
221 spin_unlock(&sbi
->fs_lock
);
223 if (read_seqretry(&rename_lock
, seq
))
229 static struct autofs_wait_queue
*
230 autofs4_find_wait(struct autofs_sb_info
*sbi
, struct qstr
*qstr
)
232 struct autofs_wait_queue
*wq
;
234 for (wq
= sbi
->queues
; wq
; wq
= wq
->next
) {
235 if (wq
->name
.hash
== qstr
->hash
&&
236 wq
->name
.len
== qstr
->len
&&
238 !memcmp(wq
->name
.name
, qstr
->name
, qstr
->len
))
245 * Check if we have a valid request.
247 * 1 if the request should continue.
248 * In this case we can return an autofs_wait_queue entry if one is
249 * found or NULL to idicate a new wait needs to be created.
250 * 0 or a negative errno if the request shouldn't continue.
252 static int validate_request(struct autofs_wait_queue
**wait
,
253 struct autofs_sb_info
*sbi
,
255 struct dentry
*dentry
, enum autofs_notify notify
)
257 struct autofs_wait_queue
*wq
;
258 struct autofs_info
*ino
;
260 /* Wait in progress, continue; */
261 wq
= autofs4_find_wait(sbi
, qstr
);
269 /* If we don't yet have any info this is a new request */
270 ino
= autofs4_dentry_ino(dentry
);
275 * If we've been asked to wait on an existing expire (NFY_NONE)
276 * but there is no wait in the queue ...
278 if (notify
== NFY_NONE
) {
280 * Either we've betean the pending expire to post it's
281 * wait or it finished while we waited on the mutex.
282 * So we need to wait till either, the wait appears
283 * or the expire finishes.
286 while (ino
->flags
& AUTOFS_INF_EXPIRING
) {
287 mutex_unlock(&sbi
->wq_mutex
);
288 schedule_timeout_interruptible(HZ
/10);
289 if (mutex_lock_interruptible(&sbi
->wq_mutex
))
292 wq
= autofs4_find_wait(sbi
, qstr
);
300 * Not ideal but the status has already gone. Of the two
301 * cases where we wait on NFY_NONE neither depend on the
302 * return status of the wait.
308 * If we've been asked to trigger a mount and the request
309 * completed while we waited on the mutex ...
311 if (notify
== NFY_MOUNT
) {
312 struct dentry
*new = NULL
;
316 * If the dentry was successfully mounted while we slept
317 * on the wait queue mutex we can return success. If it
318 * isn't mounted (doesn't have submounts for the case of
319 * a multi-mount with no mount at it's base) we can
320 * continue on and create a new request.
322 if (!IS_ROOT(dentry
)) {
323 if (dentry
->d_inode
&& d_unhashed(dentry
)) {
324 struct dentry
*parent
= dentry
->d_parent
;
325 new = d_lookup(parent
, &dentry
->d_name
);
330 if (have_submounts(dentry
))
341 int autofs4_wait(struct autofs_sb_info
*sbi
, struct dentry
*dentry
,
342 enum autofs_notify notify
)
344 struct autofs_wait_queue
*wq
;
347 int status
, ret
, type
;
349 /* In catatonic mode, we don't wait for nobody */
353 if (!dentry
->d_inode
) {
355 * A wait for a negative dentry is invalid for certain
356 * cases. A direct or offset mount "always" has its mount
357 * point directory created and so the request dentry must
358 * be positive or the map key doesn't exist. The situation
359 * is very similar for indirect mounts except only dentrys
360 * in the root of the autofs file system may be negative.
362 if (autofs_type_trigger(sbi
->type
))
364 else if (!IS_ROOT(dentry
->d_parent
))
368 name
= kmalloc(NAME_MAX
+ 1, GFP_KERNEL
);
372 /* If this is a direct mount request create a dummy name */
373 if (IS_ROOT(dentry
) && autofs_type_trigger(sbi
->type
))
374 qstr
.len
= sprintf(name
, "%p", dentry
);
376 qstr
.len
= autofs4_getpath(sbi
, dentry
, &name
);
383 qstr
.hash
= full_name_hash(name
, qstr
.len
);
385 if (mutex_lock_interruptible(&sbi
->wq_mutex
)) {
390 ret
= validate_request(&wq
, sbi
, &qstr
, dentry
, notify
);
393 mutex_unlock(&sbi
->wq_mutex
);
399 /* Create a new wait queue */
400 wq
= kmalloc(sizeof(struct autofs_wait_queue
),GFP_KERNEL
);
403 mutex_unlock(&sbi
->wq_mutex
);
407 wq
->wait_queue_token
= autofs4_next_wait_queue
;
408 if (++autofs4_next_wait_queue
== 0)
409 autofs4_next_wait_queue
= 1;
410 wq
->next
= sbi
->queues
;
412 init_waitqueue_head(&wq
->queue
);
413 memcpy(&wq
->name
, &qstr
, sizeof(struct qstr
));
414 wq
->dev
= autofs4_get_dev(sbi
);
415 wq
->ino
= autofs4_get_ino(sbi
);
416 wq
->uid
= current_uid();
417 wq
->gid
= current_gid();
418 wq
->pid
= current
->pid
;
419 wq
->tgid
= current
->tgid
;
420 wq
->status
= -EINTR
; /* Status return if interrupted */
422 mutex_unlock(&sbi
->wq_mutex
);
424 if (sbi
->version
< 5) {
425 if (notify
== NFY_MOUNT
)
426 type
= autofs_ptype_missing
;
428 type
= autofs_ptype_expire_multi
;
430 if (notify
== NFY_MOUNT
)
431 type
= autofs_type_trigger(sbi
->type
) ?
432 autofs_ptype_missing_direct
:
433 autofs_ptype_missing_indirect
;
435 type
= autofs_type_trigger(sbi
->type
) ?
436 autofs_ptype_expire_direct
:
437 autofs_ptype_expire_indirect
;
440 DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
441 (unsigned long) wq
->wait_queue_token
, wq
->name
.len
,
442 wq
->name
.name
, notify
);
444 /* autofs4_notify_daemon() may block */
445 autofs4_notify_daemon(sbi
, wq
, type
);
448 mutex_unlock(&sbi
->wq_mutex
);
450 DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
451 (unsigned long) wq
->wait_queue_token
, wq
->name
.len
,
452 wq
->name
.name
, notify
);
456 * wq->name.name is NULL iff the lock is already released
457 * or the mount has been made catatonic.
460 /* Block all but "shutdown" signals while waiting */
462 unsigned long irqflags
;
464 spin_lock_irqsave(¤t
->sighand
->siglock
, irqflags
);
465 oldset
= current
->blocked
;
466 siginitsetinv(¤t
->blocked
, SHUTDOWN_SIGS
& ~oldset
.sig
[0]);
468 spin_unlock_irqrestore(¤t
->sighand
->siglock
, irqflags
);
470 wait_event_interruptible(wq
->queue
, wq
->name
.name
== NULL
);
472 spin_lock_irqsave(¤t
->sighand
->siglock
, irqflags
);
473 current
->blocked
= oldset
;
475 spin_unlock_irqrestore(¤t
->sighand
->siglock
, irqflags
);
477 DPRINTK("skipped sleeping");
483 * For direct and offset mounts we need to track the requester's
484 * uid and gid in the dentry info struct. This is so it can be
485 * supplied, on request, by the misc device ioctl interface.
486 * This is needed during daemon resatart when reconnecting
487 * to existing, active, autofs mounts. The uid and gid (and
488 * related string values) may be used for macro substitution
489 * in autofs mount maps.
492 struct autofs_info
*ino
;
493 struct dentry
*de
= NULL
;
495 /* direct mount or browsable map */
496 ino
= autofs4_dentry_ino(dentry
);
498 /* If not lookup actual dentry used */
499 de
= d_lookup(dentry
->d_parent
, &dentry
->d_name
);
501 ino
= autofs4_dentry_ino(de
);
504 /* Set mount requester */
506 spin_lock(&sbi
->fs_lock
);
509 spin_unlock(&sbi
->fs_lock
);
516 /* Are we the last process to need status? */
517 mutex_lock(&sbi
->wq_mutex
);
520 mutex_unlock(&sbi
->wq_mutex
);
526 int autofs4_wait_release(struct autofs_sb_info
*sbi
, autofs_wqt_t wait_queue_token
, int status
)
528 struct autofs_wait_queue
*wq
, **wql
;
530 mutex_lock(&sbi
->wq_mutex
);
531 for (wql
= &sbi
->queues
; (wq
= *wql
) != NULL
; wql
= &wq
->next
) {
532 if (wq
->wait_queue_token
== wait_queue_token
)
537 mutex_unlock(&sbi
->wq_mutex
);
541 *wql
= wq
->next
; /* Unlink from chain */
542 kfree(wq
->name
.name
);
543 wq
->name
.name
= NULL
; /* Do not wait on this queue */
545 wake_up_interruptible(&wq
->queue
);
548 mutex_unlock(&sbi
->wq_mutex
);